Process of and apparatus for refining petroleum



arch 8 27 F. A. MILLIFF E1' AL PROCESSl 0F AND APPARATUS FORr REFI'NING PTROLEUM I Filed Jan. 1i. 192e March 8; 1927.

PROCESS AND KPPARATUS FOR REFINING PETROLEUM Filed Jan. 11. 192e 3 Sheets-Sheet 2 March '8' 1927 F. A. MxLLlFF ET AL VPRcEss of' AND APPARATUS FOR REFINING PETRLEUM Patented Mar. 8, 1927.

" UNITED STATES' f 1,620,163 PATENT 'o1-Fica 'FRANK A. MILLIFF AND JOHN .Au MILLIFF, 0F LOS ANGELES, CALIFORNIA.

PROCESS OF AND APPARATUS FOR REFINING- EETROLEUM.

Application sied January 11, 1a2e. serial No. 80,502.

Our invention relates to a-process of and apparatus for refining petroleum.'

It is common practice in the refining of petroleum to vaporize the low boiling point hydrocarbons contained in crude oil on petroleum by hea-ting the crude to a'temperature, for instance, of 500 F. and to pass the va por mixture thus formed through a series of successive cooling dephlegmators, in each of which a vaporhaving definite end boiling points is condensed and removed. The fractions or cuts so removed -eacli form, when condensed, a commercially marketable product and they usually comprise, in order of diminishing end boiling points, gas oil, stovey oil, several grades of distillate, kerosene and gasoline. Dephlegmator plants adapted to operate in this manner are/expensive to build and have a relatively small capacity.

An objectof our invention is to provide a process of and apparatus for refining petro- -leum which WilLhave a large capacity compared to the initial cost of construction yof the apparatus.

Another object is to provide aprocess of refining petroleum which will make possible exact control of the characteristics of the various resulting products.

A' further 4object of our invention is to providel a novel fractionating unit for conxlensing a vapor of definite characteristics from a mixture of hydrocarbon vapors, in which unit the vapor mixture-1scooled to a temperature b elowthe higher end boiling point ofthe products desired, and the particles of liquid thus formed by condensation in 'the vapor mixture removed therefrom by rapidly rotating the mixture.

.It is a still further object rto provide `a vnovel apparatus for collecting and refining bodiment of the present invention.

Fig. 2 is a-vertical sectional view of a condensate separator and re-boiler of our invention.

Fig. 3 is a horizontal sectional view taken on the line '3 3 of Fig. 2.

Fig. 4 is a horizontal sectionalvievv taken on the line 4-4 of Fig. 2.

Referring in detail to the ldravvings,rthe apparatus shown in Fig. 1 has a crude oil pressure pump 10 which draws crude' oil through a pipe 11 from a crude oil storage tank 4(not shown) and forces it through primary heat exchangers 12, which are connected together inA series by means of pipes 13. Onleavin tlie'last of tlie'series of primary heat exc angers 12, thecrude oil is forced through a pipe 14, heat exchangers 15 and 16, a pipe 17, a Waterseparator 18, and a pipe 19, to a tube still 20. A gas burner 21 in the still 20 provides lire for heating the crude oil passing through the still to a temperature of approximately 500 F. From the still 20 the hot crude oil is led through a pipe 25 to a vaporizer 2G. In the vaporizer 26 the lighter hydrocarbons pass loff from the crude oil leaving a residuum which is drawn off from the bottom of the vaporizer 26, tlirougha pipe 27, through the heat exchangers 16 and 15, and thence throughy a.

pipe 28 to a residuum line 29, which leads to a residuum. storage tank (not shown).

. The mixture of vapors which 1s given off from the hot crude oil in the vaporizer 26 passes out through the vapor line 30 at the top of the vaporizer and into a. centrifuge 31, in Which all mechanically entrained liq uid is removed from the vapor mixture and drained through the gas trap conduit 33 back into the vaporiz-er 26. The dry hot vapor mixture then passes from the centrifuge 31 through av'apor line 35'to a stand* ard intercooler 36, which is part of a. first fractionatinlc,"` unit 40. TheV unit 40 com- 'prises the intercooler 36, a condensate separat-or and re-boiler 43 and a connecting vapor linel 4G.` y

The intercoo'ler 36 is standard in construction, having a vapor conduit (not shown) which connects at its upper end With the vapor line 35 ,and at its lower end with a vapor line 46. A 'jacket 47 surrounds this intercooler vapor conduit and a liquid cooling agent'drawn from a storage tank 48 is supplied by `a pump 50 through a manifold line 51 anda leader pipe 52 to the bottom of the jacketli47. A. liquid return feeder pipe 53 leads from the upper end of the jacket 47 to a return manifold 54, which returns the liquid to the storage tank 48, thus completing the -circuit of the liquid cooling agent. A temperature sensitive control valve 56 of standard make is placedin the hot oil return pipe 53 and by shutting off the low of. cooling liquid out from the jacket 47, when the temperature therein falls below a given value, this valve 56 maintains the temperature of the liquid leaving the intercooler 36 by the pipe 53 at that value. V

The condensate separator and re-boiler 43 shown .in Figs. 2, 3 and 4 has'a re-boiler vat 60 having a bottom 61, and sides62, 63, 64 and 65, which are provided with a continuous flange 66 at their upper edge.

The boiling chamber 68 of the vat 60 is divided b a series of parallel battle walls .69 into para lel aisles 70. These baffles 69 are secured upon the boftom 6l. Everyalternate baille is attached at one end to thev wall 62, while the opposite end is spaced from the the wall 64 and spaced at the opposite endv from thev wall 62. Thus as the floor 61 is 'supported in a level position a liquid introduced into the corner 75 ofthe chamber 68 must flow in series throughout the length of each` of the aisles before reachingl the corner 76, where a condensate outlet pipe 77 connects vthrough the wall 65 with the chamber 68. A condensate run-down pipe 78 connects to the outlet pipe 77 and leads through a primary crude heat exchanger 12 to a suitable condensate storage tank (not shown).

An intake residuum header box 80 is displates 86 and 87` cloe the ouer ends of the.

header boxes 80 and 82 respectively, and have intake and outlet residuum pipes 88 and 89 provided respectively therein.

The intake residuum pipe 88 connects with a hot residuum flow line 90 into which residuum is diverted from the pipe 27. The outlet residuum pipe 89 connects with a cool residuum flow line 92, which connects'with the pipe 29 which leads to a suitable residuum storage (not shown).

A series of perforated steam pipes 95 passes through the Wall 64, each extending through one of the aisles 7 0l almost to the wall 62. Each pipe has a valve 96 and connects to a steam manifold 97. The manifold97 is supplied:with steamthrough a.

header pipe 98 by a boiler 99.

A re-boiler Vdeck plate 100 rests upon and is secured to the flange 66 so as to completely cover the chamber 68. A. conical vapor dome 101 is formed centrally in the plate 100, and has a short'vent pipe102 at the apex thereof.

A cylindrical shell 103 has a iange 104 flaring outwardly from its lower edge, which rests upon vand is secured to the deck plate i100 so that the shell 103 will be disposed concentrically about the conical dome 101. At

its upper edge the shell 103 is provided with a flange 105 which supports and connects to a flange. 106 formed upon the lower edge of a short cylindrical shell 108 of equal diameter to the shell 103. l

The shell 108 has an inverted frusto-conical shaped lower extension 110 which projects downwardly into the cylindrical shell 103 below the level of the to of the re-boiler vent 102, where its' lower'e ge 112 is curled inwardly and upwardly to form a condensate trougl 113 which has formed therein.' l l A cap plate 116 covers the top lof the shell l08-and is secured to -a iange'117 formed thereon at lits upper edge. The plate 116 cooperates with the 'shell 108 and its lower extension 110 to form a condensate Separate ing chamber 120. A wet vaporinlet pipe 121 outlet holes 114 projects tangentially through the shell 108 vand opens into the chamber 120, as shown in F 3.- Aan'ge 122 on the outer end of the inlet pipey 121 connects to a iiange123 of the vapor line 46, thus joining the latter tothe pipe 121.

A vertical dry vapor outlet pipe 125 is coaxially disposed in the chamber and has an open lower end 126 disposed about the re-boiler vent 102 and passes out of the chamber 120 through the cap pate 116. A

flange 127 on the upper end of the outlet pipe is secured to a flange 128'ormed upon an inter-unit vapor pipe 130, thus connecting the pipe 125 to'the pipe 130.

An annular condensate collecting trough is -formed between the 'conical dome 101 and the shelll03. A drain tube-136 connects with the trough 135 through the deck 100 and, as shown in Figs. 2 and 4, leads with a downward slope across the top of the inf tervening baiiie plates 69 to its discharge end 137 whichis disposed. over the corner 75 of the re-boiler chamber 68.

The fractionating unit 40, as above described, is the first of a series 42 ot' identical fractionating units. A second uniti141 has an intercooler 142,1 a. vapor connecting line 143 and a condensate separator and re-boiler 144. A third unit 145 has an intercooler 146,

a vapor connecting line 147 and a condensateseparator and re-boiler 148. The inter-unit vapor line 130^connects to the inlet end of the vapor conduit (not shown) of the intercooler 142. An inter-unit vapor line 149 connects between the vapor outlet of the condensate separator and re-boiler 144 and the vapor inlet of the intercooler 146.

l/Vhile but three fractionating units 40, 141 and 145 are shown as comprising the series 42, it is to be understood that any desired number of units may be utilized in this series.

From the vapor outlet of the condensate separator and re-boiler 148, a vapor line 151 leads tok a condenser 152 which has a condensate run-down line 153 which leads through a primary heat exchanger 12 to a suitable condensate storage tank (not shown).

The fractionating units 141 and 145 have connections t the liquid cooling agent manifold pipes 51 and 54, the residuum manifold pipes 90 and 92, and the steam header 98, identical to those described for the unit 40. f

Temperature sensitive valves 155 and 156 regulate the amount of cooling liquid leaving the intercoolers 142 and 146 respectively, so as to maintain the temperatures therein at predetermined'values. Condensate run-down lines 157 and 158 are adaptedto draw oil condensate from the re-boilers 144 and 148 respectively, and each passes through a pri-y mary heat exchanger 12 to a suitable con-v densate storage tank (not shown) The operation of the apparatus above described is as follows:

The vapor mixture leaving the vaporizer 26 passes through the centrifuge 31, is dried therein, and then passes down the vapor line to the first intercooler 36. The temperature controlled Valve 56 having` been set to limit the circulation of liquid through the jacket 47 to maintain a temperature therein below that ot the entering vapor, a cooling of the vapor mixture will occur as it passesthrough the intercooler 36. This cooling will cause the condensing of those vapors in the mixture whose boiling points are some-v what higher than the temperature of the intercooler 36. 'llhe condensedv vapors will form as a mist or inelyndivided liquid in the vapor mixture.` f

The vapor mixture with this liquid, mechanically entrained therein, passes from the intercooler 36 through the vapor line 46 to the pipe 121, from which" it jis projected tangentially into the chamber 120. Due to the holes 114 to the trough 135, from which 1t escapes through the drain 136 into the corner 5 of the re-boiler vat 68. When the refining apparatus of our invention is in continuous operation, a depth of condensate which will cover the topmost of the heating tubes 85 is maintained in the re-boiler vat 68. Condensate is drawn 0H through the outlet pipe 77 at this level at substantially'7 the saine rate as it enters the re'-boiler at the corner 7 5, through the pipe 136.-v As previously described, the balile plates 69 areso disposed in the re-boiler vat 68 that the condensate entering therein at the corner 75 must pass the Whole length of eachl of the sov aisles 70 in order to reach the corner 76. v

And as the condensate covers the pipes 85, all the condensate must come into contact With the pipes 85 in all of the aisles 70. The

fioW of hot residuum through these pipes.85

is regulated so that the condensate will be caused to boil during its passage'from the. corner to the corner 76. 'This boiling will drive olii' anyliy'drocarbons in .the condensate Which are Alighter `than those desired to be extracted from the vapor mixture in the fractionating unit 40. rlhe vapors thus driven oit vby Vboiling rise through the cone 101 and the vent 102 into the mouth 126 of the vapor outlet pipe 125. When the rapidly rotating vapor mixture in the chamber 120 has moved down to the bottomvof the conical shell 110, it is deflected upwardly by the turned up edge 112 and enters the, open end 126 of the dry vapor outlet pipe 125. The rush of vapor up- Wardly past the vent tube 102 causes a suction therein, this creating a partial vacuum in the chamber 68 above .the boiling condensate. This increases the efficiency of the reboiler 60 by lowering the boiling point of the condensatertherein so as to require less heat tol be expended in re-boiling the condensate. w Y In case the dry heat supplied by the residuum pipes 85 is` not 'effective in evaporat-ing allot the lighter vapors, steam may be admitted through the perforated pipes 95 which will lower the partial vapor pressure and complete this vaporization.

The vapors driven olil by re-boilingarel nrixed with the main flow of vapor mixture' atV the upper end of the vent tube 10,2 and pass with this main flow. up the outlet pipe 125 and out therefrom into theinter-unit vapor line 130. This line conducts Ithe remaining vapor mixture to the inlet end ot the intercooler 142 of the fractionating unit 141. From here the vapor mixture passes consecutively through the units 141 and 145 in identically the same manner as it passed through the unit 40 and as above described. 1n these units 141 and 145 the intercoolers 142 and 146 are maintained at temperatures which successively decrease from the temperature of the liiitercooler 36 ofthe unit 40. Thus in each of the intercoolers in the series of fractionating units 42 the-temperature of the vapor mixture will be reduced a given number of degrees below what it wasin thel preceding fractionating unit. This decrease in .temperature is such in each intercooler as to embrace the boiling points of a certain group of the heavier .liquids contained as vapors in the uncondensed remainder of the vapor mixture. This vcooling will condense these heavier vapors, and when the vapor mixture passes on from the intercooler to the condensate separator and re-boiler of the same unit the condensed vapors will be separated from the'vapor, re-boiled and drawn off to storage.

The temperature maintained in the intercooler 146 is such that a few of the lighter hydrocarbons pass out of the condensate separator and re-boiler 148, through the vapor line 151, intothe lcondenser 152, in which they .are condensed and pass as a liquid therefrom to storage through the condensate line 153.` p

The nature'of the condensate obtained from each fractionating unit will depend upon the amount which the temperature in its intercoooler is lower than the temperature of the last preceding Iintercooler and the proportionate quantities of the vapors present in the vapor mixture. which are condensed b'y sucha drop in temperature.

Thus the succession of temperature drops by whichfthe fractional condensation of the vapor mixture is accomplished may be regulated and the whole series of individual hydrocarbon vapors ,present in the vapor .mixture may be condensed and'refined in 'any desired groups so long as the hydrocarbons of each group are adjacent to each other on the scale of relative boiling points. Thispwer to determine the group of vapors which is to be fractionally condensed and removed from the vapor mixture in each of the fractionating units is made possible by the accurate temperature 'control of the intercoolers'and the novel and efficient condensate separator-and-reboilers lof our invention. Such `a regulation of theexact groups of `hydrocarbons removed in each fractionating lunit gives a controliover the products of fractionation 'which has not previously been I culties in previously tice.

`had in' ,the-"-petroleum' refining industry. This process is particularly valuable inasmuch as it provides a simple means of dividing crude petroleum into products. of desired initial and/end boiling points and therefore overcomes one of the greatest difiiknownrefining pracprising; applying heat to thei petroleum to drive off hydrocarbon vapors therefrom; cooling the mixture of vapors'thus formed to a predetermined temperature; causing said vapor mixture to suddenly expand and 'rotate at an accelerating speed over a given distance to separate out condensate formed by cooling the vapor mixture; collecting said condensate; and causing said vapor mixture to impose a partial lvacuum upon said condensate which communicates with said Vapor mixture.

2.y A process pf refining petroleum coinprising: applying heat to the petroleum tov drive ofi'. hydrocarbon vapors therefrom;

cooling the`mixture of vapors thus formed to a predetermined temperature; causing said mixture :of vapors to rotate rapidly to separate out condensate formed therein by said cooling; collecting said condensate; causing said vapor mixture to impose a partial vacuuni upon said condensate; and reboi-ling said condensate to drive off lighter hydrocarbons than desired in the product to be formed thereby.

3; An apparatus for refining petroleum comprising: means for vaporizing a number of hydrocarbon liquids from the' crude petroleum; means for cooling the vapor mixture thus formed to ,a predetermined temperature; means for separating out the condensate formed by saidcooling by rapidly 'rotating the vapor mixture; means fory reboiling. said condensate; and suction means whereby the vapor mixture surviving the rotary separating means draws a vacuum upon the surface of the condensate in the reboiling means.

4. In an apparatus for refining petroleum, a condensate collector and rei-'boiler comprising: a vapor rotating shell of inverted frusto-conical form; means for admitting vapor tangentially into the upper end of said shell; a vapor outlet tube centrally disposed in -said shell, the lower end of which is open and is disposed a lshort distance above the bottom of said shell; a re-boiler having av revaporizing chamber, means being provided for conducting .condensate from theV bottom of said shell to said 11e-boiler; a suction tube disposed in the lower mouth ofsaid lvapor,-ou'tlet-tube; and a. hood cou' ducting vapor from said-chamber-to said suction tube.

In testimony whereof, we have hereunto set our hands at Los Angeles, California, this 24'day of December, 1925.

FRANK A. MILLIFF. JOHN A. MILLIFF.

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